J/A+A/451/435 BV(RI)c photometry of S5 0716+714 (Montagni+, 2006)
The intra-night optical variability of the bright BL Lac object S5 0716+714.
Montagni F., Maselli A., Massaro E., Nesci R., Sclavi S., Maesano M.
<Astron. Astrophys., 451, 435-442 (2006)>
=2006A&A...451..435M 2006A&A...451..435M
ADC_Keywords: BL Lac objects ; Photometry, UBVRI ; Photometry, Cousins
Keywords: BL Lac objects: general - BL Lac objects: individual: S5 0716+714 -
galaxies: active - galaxies: BL Lacertae objects
Abstract:
We address the topic of the intra-night optical variability of the
BL Lac object S5 0716+714.
To this purpose a long-term observational campaign was carried out,
from 1996 to 2003, which allowed the collection of a very large data
set, containing 10675 photometric measurements obtained in 102
nights. The source brightness varied in a range of about 2mag,
although the majority of the observations were performed when it was
in the range 13.0<R<13.75.
Variability time scales were estimated from the rates of magnitude
variation, which were found to have a distribution function well
fitted by an exponential law with a mean value of 0.027mag/h,
corresponding to an e-folding time scale of the flux τF=37.6h.
The highest rates of magnitude variation were around 0.10-0.12mag/h
and lasted less than 2h. These rates were observed only when the
source had an R magnitude <13.4, but this finding cannot be
considered significant because of the low statistical occurrence. The
distribution of τF has a well-defined modal value at 19h.
Assuming the recent estimate of the beaming factor δ about 20,
we derived a typical size of the emitting region of about
(5x1016)/(1+z)cm.
The possibility of searching for a possible correlation between the
mean magnitude variation rate and the long-term changes in the
velocity of the superluminal components in the jet is discussed.
Description:
Table 2 reports the log of all good quality observations considered in
the paper. For each night the table contains the date of observation,
the abridged JD, the UT start time, the observation duration, the
number of frames, the filter used, the mean magnitude of the source in
the used filter, the rms deviation of the magnitude difference between
two reference stars, the telescope, and the number of time intervals
used in the evaluation of the magnitude variation rates.
Table A1 reports the entire photometric data collected in a long term
observational campaign on S5 0716+714 performed from 1996 to 2003. The
table contains 10675 photometric measurements obtained in 102 nights.
For each date the measured magnitudes (not corrected for the
interstellar reddening) and their uncertainties together with the used
filter are given. The magnitude uncertainties have been evaluated by
taking into account the mean dispersion of the internal error, but not
the errors on the absolute calibration.
Objects:
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RA (2000) DE Designation(s)
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07 21 53.4 +71 20 36 S5 0716+714 = QSO 0716+714
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 59 102 Log of all good quality observations
tablea1.dat 41 10674 Observed magnitudes of S5 0716+714
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See also:
J/A+A/402/151 : S5 0716+714 UBVRI photometry (Raiteri+, 2003)
J/A+A/327/61 : BV(RI)c photometry of S5 0716+714 (Ghisellini+ 1997)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "DD/MM/YYYY" Date Observation date
12 A1 --- n_Date [*] Note on observations (1)
14- 17 I4 d JD-2449000 Abridged Julian Day from the
initial JD 2449000
20- 21 I2 h Obs.h UT start time (hour)
22 A1 --- --- [:]
23- 24 I2 min Obs.m UT start time (minute)
27- 31 F5.2 h Dur Observation Duration
34- 36 I3 --- n Number of frames
39 A1 --- Filter [BVRI] Used filter (G1)
42- 46 F5.2 mag Mean magnitude of the source
49- 53 F5.3 mag rms rms deviation (2)
56 A1 --- Tel [VGM] Telescope (3)
59 I1 --- TI Time Intervals
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Note (1): the asterisk (*) indicates a night in which the source
remained stable during the observation time window.
Note (2): RMS deviation of the magnitude difference between two reference star
Note (3): Telescope identifications as follows:
V = Vallinfreda
G = Greve
M = Monte Porzio
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "DD/MM/YYYY" Obs.Date Date of observation
14- 20 F7.4 h Obs.h Hour of observation (UT)
24- 29 F6.3 mag mag Measured magnitude of S5 0716+714
33- 37 F5.3 mag e_mag rms uncertainty on mag
41 A1 --- Filter [BVRI] Used filter (G1)
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Global notes:
Note (G1): Johnson BV and Cousins RI filters
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Acknowledgements: Enrico Massaro, enrico.massaro(at)uniroma1.it
(End) F. Montagni [Staz. Osserv. di Vallinfreda], P. Vannier [CDS] 16-May-2006